the united states has evacuated all personnel from benghazi to tripoli. officials originally believed the attack was prompted by an anti-islamic video, but said this attack was too coordinated to have been spontaneous. >> reporter: good evening from washington. these shocking murders of our diplomats serve as a reminder of how dangerous the culture clash still is between the west and much of the muslim world. and how intense the clashes now between the rivals in the race for the white house. the u.s. consulate was still burning when president obama ordered in u.s. marines to protect american officials remaining in libya. he learned this morning four diplomats were dead. >> the united states condemns in the strongest terms this outrageous and shocking attack. >> reporter: riots preceded the deaths, first in cairo, then in benghazi, libya's number two city, well known to u.s. ambassador chris stevens. he was there when u.s. air raids prevented a massacre by moammar gadhafi. stevens reportedly braved the riot to help evacuate his people but was killed along